STEN Score

What is a STEN score?

STEN scores (or “Standard Tens”) divide a scale into ten units. In simple terms, you can think of them as “scores out of ten”:

A STEN of 1 or 2 is far below average,

A STEN of 5-7 is average,

A STEN of 9 or 10 is far above average.

STEN scores and Bell Curves

However, STEN scores don’t break up scores into 10 even chunks of 10%. They are based on the bell curve, so the vast majority of people will fall into the “average” range. Very few people (about 2%) will get either the lowest score of 1 or the highest score of 10. The average STEN score is 5.5:

STEN scores and the equivalent z-scores.

Converting Z-Scores to STEN

Z-scores are commonly used in statistics as a measure of spread. One z-score is equal to one standard deviation (either above or below the mean). To convert a z-score to a STEN score, just multiply the z-score by the standard deviation and add the mean. As a formula, that’s:

STEN = z(SD)+M

For example, if you wanted to convert a z-score of 2 to a STEN Score:
STEN = 2(2)+5.5 = 9.5.

STEN scores are always rounded up, so a score of 9.5 would be rounded to 10.